In Los Angeles, New York and Washington, D.C., anxious parents and kids who share their anxiety gather.

They draw numbers, sit in a crowded gym, cross their fingers and hope for the best.

What they’re hoping for is a chance at a future. They’re participating in a lottery, which is how kids are selected for for the nation’s prized charter schools, which out-perform entrenched public schools. No matter how poor you are, how disadvantaged your neighborhood, if you child lands a coveted charter slot, it’s good-bye to the “failure factory” that many American public schools have become.

That lottery scene is the climax to Davis Guggenheim’s “Waiting for Superman,” a heavily-hyped new expose of America’s failing schools from the director of “An Inconvenient Truth.” It was also the heart of “The Lottery,” which beat “Superman” into film festivals and theaters. The documentaries share ideas and even interview subjects. It’s the “Superman” hype that has teacher’s unions up in arms over “Waiting for Superman’s” “unions are the problem” message.

Geoffrey Canada is a charismatic New York charter school principal who appears in both films. He provided the title to “Waiting for Superman,” relating how he, as a poor child, wept on hearing there was no real Man of Steel who could come solve all the problems of his neighborhood and his school. Canada leads a Harlem charter school that has become the poster school for this subject — offering statistical proof that it’s not the kids, it’s what schools demand and the great teachers in them that make the difference.

Guggenheim interviews educators, journalists and parents and lays out damning stats about the state of our schools. He passes the blame from president to president, political party to political party, as the unions that protect bad teachers from being dismissed back Democrats at the Congressional level, Republicans at the state level, hedging their bets so that no change is ever imposed upon them.

Principals from Milwaukee to Pittsburgh break down the idea that kids start out with promise, often get through elementary school with that promise intact, only to run into a middle school where they hit the wall — maybe a bad teacher or two. Then it’s on to a high school “dropout factory,” utterly derailing their future hopes by their late teens.

We are told, time and again, about “a system with an infinite power to resist reform,” and time and again — principals and reporters point to the two big national teacher’s unions as the culprits. We see Michelle Rhee, the inexperienced administrator brought in to shake up Washington’s awful schools, butt her head against bureaucracy, unions and parents alarmed at change.

Like “The Lottery,” Guggenheim’s film focuses on parents who care, who sacrifice and put the effort into ensuring their child’s success . Like that film, it doesn’t place any of the blame for this 35 year downward educational spiral on pressures on the family and distractions and demands placed on today’s students.

The film is more overwhelming than uplifting. The solution, Guggenheim & Co. preach, is to first get everybody on the same page, pledging to see “Waiting for Superman” and connecting with many facets of the problem. Urging duplication of the formulas that KIPP (Knowledge is Power Program) and Harlem Success Academy and others are finding success with is a noble goal.

But cherry picking your subjects to suggest that all families share the same commitment (something “The Lottery” didn’t do) undercuts Guggenheim’s efforts to lay all the blame on the provably broken parts of the “system.” That’s an inconvenient truth he conspicuously avoids.